Background: Eltrombopag is effective and safe for treating chronic immune thrombocytopenia (ITP) patients who have not responded to previous therapy. Interestingly, some patients in whom hemostatic platelet counts are achieved with eltrombopag may sustain the platelet response when eltrombopag ceases to be administered. However, the frequency of sustained responses after discontinuing eltrombopag without additional therapy for ITP is largely unknown. Methods: A total of 260 adult patients (aged 18 years or more) with primary ITP treated with eltrombopag included in the Spanish Eltrombopag Registry were retrospectively evaluated. The study was performed in accordance with the standards of the Helsinki declaration and approved by the Hospital Universitario de Burgos Ethics Committee. Results: The median age was 62 [range, 18–93] years. There were 165 women and 95 men. According to the standard definition, patients were allocated to newly diagnosed (n=29), persistent (n=36) and chronic (n=195) ITP groups. The median time from diagnosis to eltrombopag initiation was 24 [range, 1–480] months. The median number of previous therapies was 3 [range, 0–10], including splenectomy (22%), rituximab (23%) and romiplostim (19%). The initial response rate to eltrombopag was 231/260 (89%), including 77% (n=201) cases of complete remission (platelet count ≥100 x 109/L). The median duration of eltrombopag treatment was 6 [range, 1–54] months. Eltrombopag was discontinued in 80 out of 201 (39.8%) patients who achieved CR. Reasons for eltrombopag discontinuation were: persistent response despite a reduction in dose over time (n=33), platelet count >400x109/L (n=29), patient’s request (n=5), aspartate aminotransferase elevation (n=3), diarrhea (n=3), thrombosis (n=3) and other reasons (n=4). For analysis of discontinuation, patients with follow-up < 6 months (n=15), newly diagnosed ITP (n=11) or patients who received concomitant or previous (6 months before) treatments at the start of eltrombopag use (n=5) were excluded. Of the 49 evaluable patients, 22 (45%) had an immediate relapse after stopping eltrombopag. One patient with sustained response after stopping treatment relapsed at 10 months. A total of 26 patients (53%) showed sustained response after discontinuing eltrombopag without additional ITP therapy, with a median follow-up of 9 [range, 6–25] months. These patients were characterized by a median time since ITP diagnosis of 46.5±114.1 months, with 4/26 having ITP <1 year. Eleven patients (42%) were male and their median age was 59 [range, 18-88] years. They had received a median of four previous treatment lines [range: 0–9 lines] and 11 (42%) were splenectomized. The median platelet count before starting eltrombopag was 22 x 109/L and that before eltrombopag withdrawal was 269 x 109/L. The main characteristics (age, gender, duration of ITP, prior anti-ITP lines, prior splenectomy, prior rituximab, prior romiplostim, platelet count before starting eltrombopag, duration of eltrombopag treatment, and platelet count before eltrombopag withdrawal) of the 26 patients with sustained response after stopping eltrombopag were compared with those of the 23 patients relapsing after eltrombopag withdrawal. No predictive factors of sustained response after eltrombopag withdrawal could be identified. Conclusion: Platelet response following eltrombopag cessation may be sustained in nearly half of adult patients with primary ITP after CR with eltrombopag. However, reliable markers for predicting which patients will have this response are lacking. Disclosures No relevant conflicts of interest to declare.

Eltrombopag is effective and safe in immune thrombocytopenia (ITP). Some patients may sustain their platelet response when treatment is withdrawn but the frequency of this phenomenon is unknown. We retrospectively evaluated 260 adult primary ITP patients (165 women and 95 men; median age, 62 years) treated with eltrombopag after a median time from diagnosis of 24 months. Among the 201 patients who achieved a complete remission (platelet count >100 3 10 9 /l), eltrombopag was discontinued in 80 patients. Reasons for eltrombopag discontinuation were: persistent response despite a reduction in dose over time (n = 33), platelet count >400 3 10 9 /l (n = 29), patient's request (n = 5), elevated aspartate aminotransferase (n = 3), diarrhea (n = 3), thrombosis (n = 3), and other reasons (n = 4). Of the 49 evaluable patients, 26 patients showed sustained response after discontinuing eltrombopag without additional ITP therapy, with a median follow-up of 9 (range, 6-25) months. These patients were characterized by a median time since ITP diagnosis of 46.5 months, with 4/26 having ITP < 1 year. Eleven patients were male and their median age was 59 years. They received a median of 4 previous treatment lines and 42% were splenectomized. No predictive factors of sustained response after eltrombopag withdrawal were identified. Platelet response following eltrombopag cessation may be sustained in an important percentage of adult primary ITP patients who achieved CR with eltrombopag. However, reliable markers for predicting which patients will have this response are needed.Am. J. Hematol. 90:E40-E43,

Eltrombopag is highly effective and well tolerated in unselected patients with primary chronic ITP.

Eltrombopag is a second-line treatment in primary immune thrombocytopenia (ITP). However, its role in secondary ITP is unknown. We evaluated the efficacy and safety of eltrombopag in secondary ITP in daily clinical practice. Eighty-seven secondary ITP patients (46 with ITP secondary to autoimmune syndromes, 23 with ITP secondary to a neoplastic disease subtype: lymphoproliferative disorders [LPDs] and 18 with ITP secondary to viral infections) who had been treated with eltrombopag were retrospectively evaluated. Forty-four patients (38%) had a platelet response, including 40 (35%) with complete responses. Median time to platelet response was 15 days (95% confidence interval, 7-28 days), and was longer in the LPD-ITP group. Platelet response rate was significantly lower in the LPD-ITP than in other groups. However, having achieved response, there were no significant differences between the durable response of the groups. Forty-three patients (49·4%) experienced adverse events (mainly grade 1-2), the commonest being hepatobiliary laboratory abnormalities. There were 10 deaths in this case series, all of which were related to pre-existing medical conditions. In routine clinical practice, eltrombopag is effective and well-tolerated in unselected patients with ITP secondary to both immune and infectious disorders. However, the response rate in LPD-ITP is low.

Summary This case report describes a 65-year-old man with a Rendu-Osler-Weber syndrome with secondary chronic anaemia, who received multiple intravenous (IV) iron infusions and sustained diffuse bone pain secondary to multiple insufficiency fractures. Laboratory study confirmed fibroblast growth factor 23 (FGF-23)-mediated hypophosphatemia as the main cause of a severe osteomalacia induced by ferric carboxymaltose (FCM). After 3 months or oral phosphate replacement and switching to iron sucrose, serum phosphate levels were normalized and patient improved clinically. Introduction Some drugs can induce asymptomatic hypophosphatemia, which if sustained, can lead to a severe osteomalacia with multiple skeletal fractures. This complication has also been described with IV iron therapy. Methods This case report describes a patient with Rendu-Osler-Weber syndrome with chronic iron deficiency anaemia, recurrently treated with FCM, who developed a severe osteomalacia with multiple skeletal fractures. Results Laboratory study showed hypophosphatemia, with high ALP and high FGF-23. Images studies confirmed bone mass loss and multiple insufficiency fractures. A Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) did not show hidden tumor, so a diagnosis of FCM-induced hypophosphatemic osteomalacia was performed. Phosphate replacement improved clinical symptoms of the patient. Conclusion Intravenous iron therapy, mainly FCM form, can cause hypophosphatemia, and in some cases induce a severe osteomalacia with multiple fractures, so it seems advisable to monitor serum phosphate levels in high risk patients, as those who receive repeated dose.